//
// Author:
//   Jb Evain (jbevain@gmail.com)
//
// Copyright (c) 2008 - 2015 Jb Evain
// Copyright (c) 2008 - 2011 Novell, Inc.
//
// Licensed under the MIT/X11 license.
//

namespace ILRuntime.Mono.Cecil
{

    public interface IConstantProvider : IMetadataTokenProvider
    {

        bool HasConstant { get; set; }
        object Constant { get; set; }
    }

    static partial class Mixin
    {

        internal static object NoValue = new object();
        internal static object NotResolved = new object();

        public static void ResolveConstant(
            this IConstantProvider self,
            ref object constant,
            ModuleDefinition module)
        {
            if (module == null)
            {
                constant = Mixin.NoValue;
                return;
            }

            lock (module.SyncRoot)
            {
                if (constant != Mixin.NotResolved)
                    return;
                if (module.HasImage())
                    constant = module.Read(self, (provider, reader) => reader.ReadConstant(provider));
                else
                    constant = Mixin.NoValue;
            }
        }
    }
}
